NEW DELHI, India — Reversing decades of U.S. policy, President Bush ushered India into the world’s exclusive nuclear club Thursday with a landmark agreement to share nuclear reactors, fuel and expertise with this energy-starved nation in return for its acceptance of international safeguards.

Eight months in the making, the accord would end India’s long isolation as a nuclear maverick that defied world appeals and developed nuclear weapons. India agreed to separate its tightly entwined nuclear industry — declaring 14 reactors as commercial facilities and eight as military — and to open the civilian side to international inspections for the first time.

The agreement must be approved by Congress, and Bush acknowledged that might be difficult because India still refuses to sign the Nuclear Non-proliferation Treaty.

(That fact has complicated other relationships. Australian Foreign Minister Alexander Downer said Friday that Australia will not sell uranium to India until it signs the treaty.

(Downer welcomed the deal brokered by Bush and Indian Prime Minister Manmohan Singh, but he said Australia would not alter its longstanding policy blocking the sale of uranium, as it could result in other countries that have not signed the treaty making bids for Australian uranium.)

Singh hails historic moment
Bush, who has made improving relations with India a goal of his administration, said “I’m trying to think differently, not stay stuck in the past.” Celebrating their agreement, Singh said, “We have made history today, and I thank you.”

U.S. officials said there was evidence the U.S. diplomat, foreign service officer David Foy, was targeted.

“Terrorists and killers are not going to prevent me from going to Pakistan,” Bush said at a news conference with Singh in New Delhi.

Aides acknowledge riskBush aides said there were security concerns about the president going to Pakistan but that officials were satisfied adequate precautions were in place. “But this is not a risk-free undertaking,” said national security adviser Stephen Hadley.

The U.S.-India nuclear deal was seen as the centerpiece of better relations between the world’s oldest and most powerful democracy and the world’s largest and fastest-growing one.

India has more than 1 billion people, and its booming economy has created millions of jobs along with consumer demands that have attracted American businesses. India’s middle class has swelled to 300 million — more than the population of the United States. Still, 80 percent of Indians live on less than $2 a day.

Bush acknowledged that Washington and New Delhi were estranged during the Cold War, when India declared itself a nonaligned nation but tilted toward Moscow. “Now the relationship is changing dramatically,” he said.

Bush began the day by paying respects at a memorial to Mohandas K. Gandhi, India’s independence leader and apostle of nonviolence. Following tradition, the president and his wife, Laura, left their shoes behind. Bush also conferred with the CEOs of Indian and American businesses, religious leaders and the head of India’s political opposition.

Bush and Singh announced new bilateral cooperation on issues from investment, trade and health to agriculture, the environment and even mangoes. Bush agreed to resume imports of the juicy, large-pitted fruit after a 17-year ban.

The president ended the day at a state dinner with Indian President A.P.J. Abdul Kalam under a crescent moon in a lush courtyard of the presidential palace.

Sealing the deal with mango juice
Waiters in red tunics and red-and-white turbans scurried to serve broccoli-almond soup, seafood and peach ice cream after toasts of mango juice by the two heads of state.

The nuclear agreement drew fire from congressional critics.

“With one simple move the president has blown a hole in the nuclear rules that the entire world has been playing by, and broken his own word to assure that we will not ship nuclear technology to India without the proper safeguards,” said Rep. Edward Markey of Massachusetts, senior Democrat on the House Energy and Commerce Committee.

In New York, John Bolton, the U.S. ambassador to the United Nations, defended the deal. “India and Pakistan had never signed the Non-Proliferation Treaty and therefore, they weren’t in violation of it by having nuclear programs,” he said.

Bush said helping India with nuclear power would reduce the global demand for energy which has sent gasoline prices soaring.

“To the extent that we can reduce demand for fossil fuels, it will help the American consumer,” Bush said.

It also could be a boon for American companies that have been barred from selling reactors and material to India.

Critics have complained the deal rewards bad behavior and undermines efforts to prevent states like Iran and North Korea from acquiring nuclear weapons. The White House said India was unique because it had protected its nuclear technology and not been a proliferator.

Administration rebuts critics
The administration also argued it was a good deal because it would provide international oversight for a program that has been secret since India entered the nuclear age in 1974.

“In its largest sense, in the geopolitical sense, the agreement today removes a basic irritant in the relations between India and the United States over the last 30 years,” said Nick Burns, undersecretary of state for political affairs.”

The agreement has no impact on India’s nuclear weapons program. “It’s not a perfect deal in the sense that we haven’t captured 100 percent of India’s nuclear program,” Burns acknowledged.

The agreement grew out of an accord Bush and Singh signed last July to establish a new relationship in civil nuclear energy.

The United States and other countries slapped sanctions on India and Pakistan after they conducted nuclear weapons tests 1998 but those penalties were lifted after the terrorist attacks of Sept. 11, 2001, when the United States sought allies against al-Qaida.